Re: [CAD_CAM_EDM_DRO] Re: BDI and servos

At 09:07 12/7/2002 -0600, you wrote:

>I saw a demo of a mill that ran with either the usual velocity control
>from the EMC or current control using the same computations. The
>velocity control included amps that used tach signals for speed feedback
>while the current loop ignored the tach signals and used position
>computation right out of the PC. I couldn't tell the difference in
>control of the motors during accel/decel or during smooth motion at most
>any speed. But having said this I have to say that the guy that did the
>demo had some pretty sophisticated proprietary tuning routines and knew
>how to use them.

Thanks Ray

I've had very good luck running servos in current mode as opposed to
velocity mode. The trick seems to be having high enough encoder counts and
update rate to keep things smooth. The nice thing about current mode is the
tuning becomes a lot easier since the velocity loop is not mixed into the mess.

I think I'd like to stick to a motion board of some type. I'm more familiar
with this type of setup with other retrofits I've done.

I know I've seen it here before, but I forget...How do I contact you to
purchase for copy of BDI? (Off list bsimon@... if need be)

-Bob